miscellaneous: experimental teratosis 631 



1906. Johannsen,W. Das Aetherverfahren beim Friihtrei- 

 ben, mit besonderer Beriicksichtigung der Fliedertreiberei. 2 

 Aufl., pp. 65. Jena. Gustav Fischer, 1906. 



1909. Molisch, Hans. Das Warmbad als Mittel zum 

 Treiben der Pflanzen. Jena. Verlag von Gustav Fischer. 1909, 

 pp. IV, 38. Mit 12 Figuren im Text. 



additional literature on intumescences 

 (See page 572) 



1898. Tubeuf, C. von. Uber Lenticellen-Wucherungen 

 (Aerenchym) an Holzewachsen. Forstlich-naturwissenschaftliche 

 Zeitschrift, VII Jahrgang, 12 Heft, December, 1898, pp. 405- 

 414, 7 Figs. 



This very interesting paper, which was read with fear and trembling, came 

 to mj^ knowledge too late to be mentioned in the body of the text (page 477 

 et seq.), i.e., not until the corrected proofs had been returned to the printer. It 

 anticipates by twenty years some of my findings but not all. The author 

 raises the question of reduced transpiration as a possible cause of the tumors 

 and decides against it because he also obtained them in his closed vessels when 

 projecting leaves were on the plant and transpiration was in progress, but if the 

 fluid transpired possessed a limited oxygen-content as it must in closed tubes," 

 the peripheral stem tissues would still receive insuflficient oxygen; and they 

 might even, if the water transpired by the leaves, had sufficient oxygen, i.e., 

 was ground water, since the moist air in contact with the lenticels in the closed 

 chambers would soon become deficient in oxygen. Concerning increased acidity 

 of such tissues it does not appear to have occurred to Dr. Tubeuf to make 

 any inquiries. 



Von Tubeuf states that the proliferation may be so extreme as to be patho- 

 logical and that it is not due to an excess of water in the tissues. He cites 

 Goebel to the effect that it arises in consequence of an undetermined irritation 

 and Schenk that " it is not very probable that simple contact of the epidermis 

 with the water, as such, is a factor, it is much rather to be supposed that lack 

 of oxygen in the inner tissues, the plasma of the phellogen cells, leads to the 

 production of the aerenchym." 



Dr. Tubeuf's experiments were made with stems and roots of small trees — 

 elms, etc. 



1913. Wehmer, C. Ubergang iilterer • Vegetationem von 

 Aspergillus fumigatus in " Riesenzellen " unter Wirkung ange- 

 haufter Saure. Berichte der Deutschen Botanischen Gesellschaft, 

 Vol. XXXI, No. 5, 1913-1914, pp. 257-274, 7 text figures. 



Wehmer obtained great numbers of giant cells in cultures of Aspergillus and 

 Penicillium, using ammonium sulphate. He attributes these giant cells to the 

 action of free acid ions on the spores of the fungus. 



